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  • embryo
  • In many animals, the germ cells originate in the primitive streak and migrate via the gut of an embryo to the developing gonads. (wikipedia.org)
  • There are two mechanisms to establish the germ cell lineage in the embryo. (wikipedia.org)
  • citation needed] In the model organism Drosophila, pole cells passively move from the posterior end of the embryo to the posterior midgut because of the infolding of the blastoderm. (wikipedia.org)
  • Taken together, our results indicate that the CRISPR/Cas9 system can mediate stable gene knockdown at the cell and embryo levels in domestic chickens. (g3journal.org)
  • In general, in organisms that reproduce sexually , an embryo develops from a zygote , the single cell resulting from the fertilization of the female egg cell by the male sperm cell. (wikipedia.org)
  • The position and arrangement of the germ layers are highly species-specific, however, depending on the type of embryo produced. (wikipedia.org)
  • In botany , a seed plant embryo is part of a seed , consisting of precursor tissues for the leaves, stem (see hypocotyl ), and root (see radicle ), as well as one or more cotyledons . (wikipedia.org)
  • In these plants, the embryo begins its existence attached to the inside of the archegonium on a parental gametophyte from which the egg cell was generated. (wikipedia.org)
  • this "foot" consists of a bulbous mass of cells at the base of the embryo which may receive nutrition from its parent gametophyte. (wikipedia.org)
  • The structure and development of the rest of the embryo varies by group of plants. (wikipedia.org)
  • From fertilization through gastrulation an animal embryo experiences an exponential increase in cell number and undergoes dramatic reorganization forming specialized germ layers. (sdbcore.org)
  • However, cell pluripotency is a continuum, ranging from the completely pluripotent cell that can form every cell of the embryo proper, e.g., embryonic stem cells and iPSCs (see below), to the incompletely or partially pluripotent cell that can form cells of all three germ layers but that may not exhibit all the characteristics of completely pluripotent cells. (wikipedia.org)
  • In flowering plants, the male gametophyte produces a pair of functional sperm cells that are transported to the embryo sac for double fertilisation. (le.ac.uk)
  • The resulting combination of proteins will transform clusters of cells into early embryo tissues that will each develop into multiple fetal and adult tissues later in development (note: this happens after each nucleus becomes wrapped with its own cell membrane). (wikipedia.org)
  • In humans, the term embryo refers to the ball of dividing cells from the moment the zygote implants itself in the uterus wall until the end of the eighth week after conception. (wikipedia.org)
  • For example, in the neural plate of the embryo this system operates to generate a population of neuronal precursor cells in which NeuroD is highly expressed. (wikipedia.org)
  • In more derived flowering plants the embryo occupies most of the seed and the endosperm is non developed or consumed before the seed matures. (wikipedia.org)
  • Also, most basal angiosperms still contain the four-cell embryo sac and produce diploid endosperms. (wikipedia.org)
  • Nonflowering seed plants (conifers, cycads, Ginkgo, Ephedra) form a large homozygous female gametophyte to nourish the embryo within a seed. (wikipedia.org)
  • The early embryo "syncytium" of invertebrates such as Drosophila is important for "syncytial" specification of cell differentiation. (wikipedia.org)
  • nuclei
  • Sex in eukaryotes is a composite process, consisting of meiosis and fertilization (or, more generally, 'mixis', the process of fusion of cells and nuclei), which can be coupled to reproduction [ 3 ]. (royalsocietypublishing.org)
  • A series of nuclear divisions will occur without cytokinesis (division of the cell) in the zygote to form a multi-nucleated cell (a cell containing multiple nuclei) known as a syncytium. (wikipedia.org)
  • All the nuclei in the syncytium are identical, just as all the nuclei in every somatic cell of any multicellular organism are identical in terms of the DNA sequence of the genome. (wikipedia.org)
  • Each of the approximately 100 trillion (1014) cells in an adult human has its own copy or copies of the genome except certain cell types, such as red blood cells, that lack nuclei in their fully differentiated state. (wikipedia.org)
  • One species of flowering plant, Nuphar polysepala, has been shown to have endosperm that is diploid, resulting from the fusion of a pollen nucleus with one, rather than two, maternal nuclei. (wikipedia.org)
  • In contrast to the Cladophorales where nuclei are organized in regularly spaced cytoplasmic domains, the cytoplasm of Bryopsidales exhibits streaming, enabling transportation of organelles, transcripts and nutrients across the plant. (wikipedia.org)
  • Ciliates have cells that contain two nuclei: a macronucleus and a micronucleus. (wikipedia.org)
  • Those nuclei with more Bicoid will activate genes that promote differentiation of cells into head and thorax structures. (wikipedia.org)
  • Nuclei exposed to more Nanos will activate genes responsible for differentiation of posterior regions, such as the abdomen and germ cells. (wikipedia.org)
  • proliferating cell nu
  • During replication, DNA polymerases working on the leading and lagging strands are coupled by the DNA processivity factor proliferating cell nuclear antigen (PCNA), which has also been implicated in patterning and strand crosstalk that allows for copy fidelity of epigenetic marks. (wikipedia.org)
  • plasm
  • The first way is called preformistic and involves that the cells destined to become germ cells inherit the specific germ cell determinants present in the germ plasm (specific area of the cytoplasm) of the egg (ovum). (wikipedia.org)
  • Some authors suggest that Strasburger based the terms on Weismann's conception of the id (or germ plasm), hence haplo-id and diplo-id. (wikipedia.org)
  • mechanisms
  • B M B 251 (MICRB 251) Molecular and Cell Biology I (3) Biomolecules, genetic mechanisms, organization of cells and their organelles, DNA replication, protein synthesis, membranes, the cell nucleus, energy conversion. (psu.edu)
  • Differential inheritance of epigenetic marks due to underlying maternal or paternal biases in removal or retention mechanisms may lead to the assignment of epigenetic causation to some parent of origin effects in animals and plants. (wikipedia.org)
  • The host, an archaeon, most probably already had repair mechanisms based on DNA pairing and recombination, and possibly some kind of primitive cell fusion mechanism. (royalsocietypublishing.org)
  • terminally differentiated
  • The Arabidopsis germ line derives from the unequal division of the microspore, producing a small germ cell and a large terminally differentiated vegetative cell. (le.ac.uk)
  • After formation of the three germ layers, cells will continue to specialize until they reach a terminally differentiated state that is much more resistant to changes in cell type than its progenitors. (wikipedia.org)
  • fungi
  • 4. A recombinant DNA molecule according to claim 3 , wherein the said structural gene upon expression leads to resistance against plant pathogens selected from the group consisting of insects, fungi, bacteria and viruses. (google.com)
  • Animals have evolved a greater diversity of cell types in a multicellular body (100-150 different cell types), compared with 10-20 in plants, fungi, and protoctists. (wikipedia.org)
  • In some plants, fungi, and protists meiosis results in the formation of spores: haploid cells that can divide vegetatively without undergoing fertilization. (wikipedia.org)
  • Rust fungi only form appressoria at stomata, since they can only infect plants through these pores. (wikipedia.org)
  • Other fungi tend to form appressoria over anticlinal cell walls and some form them at any location. (wikipedia.org)
  • It evolved repeatedly for Chloroplastida (green algae and land plants), once or twice for animals, once for brown algae, three times in the fungi (chytrids, ascomycetes and basidiomycetes) and perhaps several times for slime molds and red algae. (wikipedia.org)
  • Animals have evolved a considerable diversity of cell types in a multicellular body (100-150 different cell types), compared with 10-20 in plants and fungi. (wikipedia.org)
  • blastomeres
  • citation needed] In the Xenopus egg, the germ cell determinants are found in the most vegetal blastomeres. (wikipedia.org)
  • The blastula stage typically features a fluid-filled cavity, the blastocoel , surrounded by a sphere or sheet of cells, also called blastomeres . (wikipedia.org)
  • In mammals, only the zygote and subsequent blastomeres are totipotent, while in plants many differentiated cells can become totipotent with simple laboratory techniques. (wikipedia.org)
  • totipotent
  • Spores and zygotes are examples of totipotent cells. (wikipedia.org)
  • Human development begins when a sperm fertilizes an egg and the resulting fertilized egg creates a single totipotent cell, a zygote. (wikipedia.org)
  • After reaching a 16-cell stage, the totipotent cells of the morula differentiate into cells that will eventually become either the blastocyst's Inner cell mass or the outer trophoblasts. (wikipedia.org)
  • Approximately four days after fertilization and after several cycles of cell division, these totipotent cells begin to specialize. (wikipedia.org)
  • Arabidopsis
  • Leicester Research Archive: Proliferation and cell fate establishment during Arabidopsis male gametogenesis depends on the Retinoblastoma protein. (le.ac.uk)
  • Proliferation and cell fate establishment during Arabidopsis male gametogenesis depends on the Retinoblastoma protein. (le.ac.uk)
  • proteins
  • Piwi proteins are highly conserved RNA-binding proteins and are present in both plants and animals. (wikipedia.org)
  • Recently identified as a polar granule component, PIWI proteins appear to control germ cell formation so much so that in the absence of PIWI proteins there is a significant decrease in germ cell formation. (wikipedia.org)
  • Recent evidence suggests that the functional role of piwi proteins in germ-line determination is due to their capacity to interact with miRNAs. (wikipedia.org)
  • Differentiated cells contain large amounts of specific proteins associated with the cell function. (wikipedia.org)
  • Differentiated cells usually produce large amounts of a few proteins that are required for their specific function and this gives them the characteristic appearance that enables them to be recognized under the light microscope. (wikipedia.org)
  • meiotic
  • To study the function of SirT1 specifically in the male germ line, we deleted this sirtuin in male germ cells and found that mutant mice had smaller testes, a delay in differentiation of pre-meiotic germ cells, decreased spermatozoa number, an increased proportion of abnormal spermatozoa and reduced fertility. (biologists.org)
  • Immediately following DNA replication, meiotic cells enter a prolonged G2-like stage known as meiotic prophase. (wikipedia.org)
  • In female animals, three of the four meiotic products are typically eliminated by extrusion into polar bodies, and only one cell develops to produce an ovum. (wikipedia.org)
  • In the first meiotic division, the homologs are segregated to separate daughter cells by the spindle apparatus. (wikipedia.org)
  • signals
  • 2. A recombinant DNA molecule according to claim 1 , wherein the said DNA comprises a chimaeric DNA construct comprising an expressible DNA in operable linkage with expression signals active in plant cells, wherein said expression signals are selected from the group consisting of promoter and termination sequences. (google.com)
  • Following spore attachment and germination on the host surface, the emerging germ tube perceives physical cues such as surface hardness and hydrophobicity, as well as chemical signals including wax monomers that trigger appressorium formation. (wikipedia.org)
  • Appressoria are induced in response to physical cues including surface hardness and hydrophobicity, as well as chemical signals of exogenous cAMP, ethylene, the host's ripening hormone and the plant cutin monomer, hexadecanoic acid. (wikipedia.org)
  • diploid
  • For example, diploid human cells contain 23 pairs of chromosomes including 1 pair of sex chromosomes (46 total), half of maternal origin and half of paternal origin. (wikipedia.org)
  • Although the process of meiosis is related to the more general cell division process of mitosis, it differs in two important respects: Meiosis begins with a diploid cell, which contains two copies of each chromosome, termed homologs. (wikipedia.org)
  • mitosis
  • The mitosis first occurs soon after surface attachment and a nucleus from the second round of mitosis during tip swelling migrates into the hooked cell before septum formation. (wikipedia.org)
  • zygote
  • One sperm nucleus fertilizes the egg cell, forming a zygote, while the other sperm nucleus usually fuses with the binucleate central cell, forming a primary endosperm cell (its nucleus is often called the triple fusion nucleus). (wikipedia.org)
  • pluripotent
  • Virally induced expression of four transcription factors Oct4, Sox2, c-Myc, and Kfl4 (Yamanaka factors) is sufficient to create pluripotent (iPS) cells from adult fibroblasts. (wikipedia.org)
  • These cells are referred to as pluripotent. (wikipedia.org)
  • molecular
  • B M B 406 Molecular Biology (3) A discussion of current aspects of cell molecular biology with a laboratory emphasizing current biotechnology techniques. (psu.edu)
  • Molecular Plant-Microbe Interactions. (wikipedia.org)
  • occurs
  • Parthenogenesis occurs naturally in some species, including lower plants (where it is called apomixis), invertebrates (e.g. water fleas, aphids, some bees and parasitic wasps), and vertebrates (e.g. some reptiles, fish, and, very rarely, birds and sharks). (wikipedia.org)
  • Growth mostly occurs through cell division but also through changes of cell size and the deposition of extracellular materials. (wikipedia.org)
  • Some differentiation occurs in response to antigen exposure. (wikipedia.org)
  • neural crest
  • In vertebrates , a special population of embryonic cells called the neural crest has been proposed as a "fourth germ layer", and is thought to have been an important novelty in the evolution of head structures. (wikipedia.org)
  • division
  • Differentiation of cells is driven by different environmental cues (such as cell-cell interaction) and intrinsic differences (such as those caused by the uneven distribution of molecules during division). (wikipedia.org)
  • Play media Meiosis /maɪˈoʊsɪs/ ( listen) is a specialized type of cell division that reduces the chromosome number by half, creating four haploid cells, each genetically distinct from the parent cell that gave rise to them. (wikipedia.org)
  • The cells then proceed to a second division without an intervening round of DNA replication. (wikipedia.org)
  • Another hypothesis is that a primitive cell underwent nucleus division, thereby becoming a coenocyte. (wikipedia.org)
  • Proliferation
  • The Retinoblastoma (Rb) protein is a conserved repressor of cell proliferation. (le.ac.uk)
  • These defects are rescued by preventing cell proliferation arising from down-regulation of cyclin-dependent kinase A1. (le.ac.uk)
  • Our results indicate that hyperproliferation caused by the loss of Rb protein prevents or delays cell determination during plant male gametogenesis, providing further evidence for a direct link between fate determination and cell proliferation. (le.ac.uk)
  • meiosis
  • Before meiosis begins, during S phase of the cell cycle, the DNA of each chromosome is replicated so that it consists of two identical sister chromatids, which remain held together through sister chromatid cohesion. (wikipedia.org)
  • transcription
  • The egg cell cytoplasm contains localized mRNA molecules such as those that encode the transcription factors Bicoid and Nanos. (wikipedia.org)
  • algae
  • Natural occurrence of boron-containing compounds in plants, algae and microorganisms. (bio.net)
  • Coenocytic cells are present in diverse and unrelated groups of algae, including Xanthophyceae (e.g. (wikipedia.org)
  • Griffithsia) and green algae (e.g., the internodal cells of Chara). (wikipedia.org)
  • In the siphonous green algae Bryopsidales and some Dasycladales the entire thallus is a single multinucleate cell, which can be many meters across (e.g. (wikipedia.org)
  • blastula
  • After cleavage, the dividing cells, or morula, becomes a hollow ball, or blastula, which develops a hole or pore at one end. (wikipedia.org)
  • chromosomes
  • The zygotic number is defined as the number of chromosomes in zygotic cells. (wikipedia.org)
  • The potato plant inherits two sets of 12 chromosomes from the pollen parent, and two sets of 12 chromosomes from the ovule parent. (wikipedia.org)